Magnet arrangement for a low-voltage circuit-breaker

Abstract

An exemplary magnet arrangement improves the running characteristics of a switching arc generated upon the interruption of a current circuit in a pre-chamber of a low-voltage circuit-breaker, in which the switching arc is directed between two electric arc running rails. The exemplary arrangement includes an open magnetic circuit having a magnetic material and at least one permanent magnet that delivers magnetic flux to the magnetic circuit, with magnetic induction generated in a vicinity of the pre-chamber acting upon the switching arc. The magnetic material can be configured as a U-section sheet metal plate which extends along the length of the pre-chamber and includes a material recess which extends through this pre-chamber metal sheet and is arranged to contain the at least one permanent magnet. The exemplary arrangement is of a simple construction and permits adjustment of magnetic induction acting in the pre-chamber of the low-voltage circuit-breaker.

What is claimed is: 
     
       1. A magnet arrangement for improving running characteristics of a switching arc generated upon an interruption of a current circuit in a pre-chamber of a low-voltage circuit-breaker, in which the switching arc is directed between two electric arc running rails, the magnet arrangement comprising:
 an open magnetic circuit comprised of a magnetic material; and 
 at least one permanent magnet that delivers a magnetic flux to the magnetic circuit and generates magnetic induction in a vicinity of the pre-chamber that acts upon the switching arc, 
 wherein the magnetic material is configured as a U-section metal sheet which extends along the length of the pre-chamber, the U-section metal sheet including a material recess that extends through a pre-chamber metal sheet and contains the at least one permanent magnet. 
 
     
     
       2. The magnet arrangement as claimed in  claim 1 , wherein two pole faces of the at least one permanent magnet for delivery of the magnetic flux to the pre-chamber metal sheet are arranged to project from the material recess on both sides of the pre-chamber metal sheet. 
     
     
       3. The magnet arrangement as claimed in  claim 1 , wherein the material recess extends along a rear face which joins two shanks of the U-section metal sheet. 
     
     
       4. The magnet arrangement as claimed in  claim 3 , wherein two pole faces of the at least one permanent magnet for delivery of the magnetic flux to the pre-chamber metal sheet are arranged to project from the material recess on both sides of the pre-chamber metal sheet. 
     
     
       5. The magnet arrangement as claimed  claim 3 , wherein the pre-chamber metal sheet is secured to a pre-chamber insulation for the electrical isolation of the metal sheet from the switching arc. 
     
     
       6. The magnet arrangement as claimed in  claim 3 , wherein the material recess is limited by a first web which connects the two shanks of the U-section metal sheet together. 
     
     
       7. The magnet arrangement as claimed in  claim 6 , wherein the material recess is limited by a second web which connects the shanks of the U-section metal sheet. 
     
     
       8. The magnet arrangement as claimed in  claim 7 , wherein the magnetic induction of the magnetic circuit acting in the pre-chamber may be adjusted by variation of the geometrical dimensions of the first web. 
     
     
       9. The magnet arrangement as claimed in  claim 6 , wherein the magnetic induction of the magnetic circuit acting in the pre-chamber may be adjusted by variation of the geometrical dimensions of the first web. 
     
     
       10. The magnet arrangement as claimed in  claim 6 , wherein two pole faces of the at least one permanent magnet for delivery of the magnetic flux to the pre-chamber metal sheet are arranged to project from the material recess on both sides of the pre-chamber metal sheet. 
     
     
       11. The magnet arrangement as claimed  claim 6 , wherein the pre-chamber metal sheet is secured to a pre-chamber insulation for the electrical isolation of the metal sheet from the switching arc. 
     
     
       12. The magnet arrangement as claimed  claim 1 , wherein the pre-chamber metal sheet is secured to a pre-chamber insulation for the electrical isolation of the metal sheet from the switching arc. 
     
     
       13. The magnet arrangement as claimed in  claim 12 , wherein attachment of the pre-chamber metal sheet to the pre-chamber insulation is provided in the form of a clip-on or plug-in arrangement. 
     
     
       14. The magnet arrangement as claimed in  claim 12 , wherein the pre-chamber metal sheet includes a marking and an exposed section of the surface of the pre-chamber insulation, indicating the associated pole of the at least one permanent magnet. 
     
     
       15. The magnet arrangement as claimed in  claim 12 , wherein the pre-chamber insulation has two sides, each side is associated with one of the two poles respectively of the at least one permanent magnet, and are provided with different coloration established by an integral coloring of a material of the pre-chamber insulation. 
     
     
       16. The magnet arrangement as claimed in  claim 12 , wherein the pre-chamber metal sheet and the pre-chamber insulation are held in an assembly unit of the low-voltage circuit-breaker. 
     
     
       17. The magnet arrangement as claimed in  claim 16 , wherein the pre-chamber metal sheet and the pre-chamber insulation are held in the assembly unit by a plug-in arrangement. 
     
     
       18. A low-voltage circuit-breaker comprising:
 a pre-chamber; 
 electric arc running rails, wherein a switching arc is directed between two of the electric arc running rails; and 
 a magnet arrangement, wherein the magnet arrangement comprises:
 an open magnetic circuit comprised of a magnetic material; and 
 at least one permanent magnet that delivers a magnetic flux to the magnetic circuit and generates magnetic induction in a vicinity of the pre-chamber that acts upon the switching arc, 
 wherein the magnetic material is configured as a U-section metal sheet which extends along the length of the pre-chamber, the U-section metal sheet including a material recess that extends through a pre-chamber metal sheet and contains the at least one permanent magnet. 
 
 
     
     
       19. The circuit-breaker as claimed in  claim 18 , in which the pre-chamber metal sheet is secured to a pre-chamber insulation for electrical isolation of the metal sheet from the switching arc, and the pre-chamber metal sheet and the pre-chamber insulation are constituent elements of an assembly unit of the circuit-breaker, wherein the assembly unit includes a housing element configured to be attached to a housing of the circuit-breaker and detachable from the circuit-breaker housing. 
     
     
       20. The circuit-breaker as claimed in  claim 19 , wherein the assembly unit is incorporated into the circuit-breaker housing by means of a positive and frictional attachment of the housing element. 
     
     
       21. The circuit breaker as claimed in  claim 20 , wherein the housing element is attached through at least one of riveting, screw fixing, or pinning.